sub interfaces 1

[wowhead]

Trying to get around this:

% Configuring IP routing on a LAN subinterface is only allowed if that subinterface is already configured as part of an IEEE 802.10, IEEE 802.1Q,or ISL vLAN.

I'm trying to get around this. What do I need to do?

 

[Belushi]

Well, you need to configure your sub-interface as part of a trunk just like the error message indicated. It's not very hard to do. You will need to configure each sub-interface as a member of a specific vlan/subnet. Then make sure that the switch you are attaching to supports the same trunking mechanism (802.1q/ISL) as the router encapsulation you are using.

 

[wowhead]

what's the syntax for that then? sorry, im a router newb.

 

[burtsbees]

router>en
router#conf t
router(config)#int fa0/0.1
router(config-subif)#encaps dot1q 1
router(config-subif)#ip add x.x.x.x y.y.y.y
router(config-subif)#exit
router(config)#int fa0/0
router(config-if)#no shut
router(config-if)#end
router#wr

That is configuring the fa0/0 with the subinterface of fa0/0.1 with 802.1q vlan trunking encapsulation for vlan 1, and x.x.x.x=ip address, y.y.y.y=mask. Fopr different vlans (I.E. vlan 20), it would be fa0/0.23, encaps dot1q 23

None of this will work if you have IP Base IOS, so if you have trouble (like "% Invalid input detected at '^' marker.), then post a sh ver.

Burt


Burt

 

[wowhead]

i think i finally made my way through all this, thanks for your help. now, I read that you are matching sub-int number with vlan number and I didnt do that...i dont think i have the heart to go back and change that, this late in the day...

 

[burtsbees]

You don't necessarily have to make the subinterface number the same as the vlan, but it helps to lessen confusion, especially when troubleshooting. Glad you got it working.
And I made a typo...
"I.E. vlan 20), it would be fa0/0.23, encaps dot1q 23"
it should be
I.E. vlan 20), it would be fa0/0.20, encaps dot1q 20

Burt